Many applications require that relatively short pulses be generated. There are many types of existing electronic devices for generating such short pulses. However, they are typically limited to the generation of pulses each having a pulse duration of one nanosecond or more. There is however a need to generate pulses having instead a pulse duration in the order of a few picoseconds, or a few tens of picoseconds. Prior art devices are typically not suitable for addressing such a need.
Typical pulse generation methods used in prior art devices involve, for example, differentiating a relatively high slew rate electrical signal, or combining an input analog signal to its inverse delayed by a relatively small delay typically chosen to be in the order of magnitude of the desired pulse duration. While these two methods of generating pulses are relatively efficient for the generation of relatively long pulses, they are typically not usable to produce very short pulses. For example, for the duration of a pulse generated using the prior art differentiation method to be in the desired range, the signal would need to increase at a rate that is not typically achievable at relatively low costs.
U.S. Pat. No. 6,433,720 issued on Aug. 13, 2002 to Libove illustrates another manner of generating pulses which basically provides for the generation of pulses having variable, adjustable or tunable, pulse durations. This is done by triggering the pulse generation at different control voltage levels of a relatively low slew rate voltage signal. Such prior art generators are however typically very sensitive to noise since any noise present in the relatively low slew rate voltage signal or in the control voltage may change the exact start and finish timings, which affect its duration.
There is thus a need for improved devices and method for generating pulses with relatively short pulse durations.